/*
 *  Copyright 2013 National Institute of Advanced Industrial Science and Technology
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.sss.common.io;

import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.sss.common.DataReceiver;
import org.sss.common.KeyValues;
import org.sss.mapreduce.Configuration;
import org.sss.mapreduce.GroupID;
import org.sss.mapreduce.IOConfiguration;
import org.sss.mapreduce.SssException;
import org.sss.mapreduce.StorageNode;

public class IOManager {
  @SuppressWarnings("unused")
  private static Logger logger = LoggerFactory.getLogger(IOManager.class);
  private IOConfiguration ioConf;

  public IOManager(IOConfiguration conf) {
    this.ioConf = conf;
  }

  public boolean isStreamProtocol() {
    return ioConf.stream_protocol;
  }

  public DataReader createDataReader(Configuration conf,
                                     StorageNode node,
                                     GroupID gid,
                                     int subhash,
                                     DataReceiver<List<byte[]>> next) throws SssException {
    // TODO: CheckDB class?
    if (isStreamProtocol()) {
      return new StreamDBFlatDataReader(conf, node, gid, subhash, next);
    }
    else if (ioConf.db_use_vanilla) {
      return new RestrictedFlatDataReader(conf, node, gid, subhash, next);
    }
    else {
      return new FlatDataReader(conf, node, gid, subhash, next);
    }
  }

  public DataReader createKeyValueReader(Configuration conf,
                                         StorageNode node,
                                         GroupID gid,
                                         int subhash,
                                         DataReceiver<List<KeyValues>> next) throws SssException {
    // TODO: CheckDB class?
    if (isStreamProtocol()) {
      return new StreamDBKeyValuesReader(conf, node, gid, subhash, next);
    }
    else if (ioConf.db_use_vanilla) {
      switch (gid.getKeyFormat()) {
        case THREAD:  return new RestrictedWorkerFirstKeyValueReader(conf, node, gid, subhash, next);
        case USERKEY: return new RestrictedRawKeyFirstKeyValueReader(conf, node, gid, subhash, next);
        case ORDER:   return new RestrictedWholeDataKeyValueReader(conf, node, gid, subhash, next);
      }
    }
    else {
      switch (gid.getKeyFormat()) {
        case THREAD:  return new WorkerFirstKeyValueReader(conf, node, gid, subhash, next);
        case USERKEY: return new RawKeyFirstKeyValueReadeer(conf, node, gid, subhash, next);
        case ORDER:   return new WholeDataKeyValueReader(conf, node, gid, subhash, next);
      }
    }
    throw new SssException("NOTREACHED");
  }

  public DataWriter createDataWriter() {
    if (isStreamProtocol()) {
      return new StreamDBDataWriter();
    }
    else {
      return new DataWriterImpl();
    }
  }
}
